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1. Field
The present invention relates to small internal combustion engines of the type that are used to power lawn mowers, tillers, lawn vacuums, weed trimmers, snow blowers, water blasters and the like. Even more particularly, the present invention relates to an improved safety fuel tank and filler cap apparatus which enters a safety mode and alerts a user who grasps and turns the fuel cap (or when the fuel cap loosens) that gasoline should not be added to the fuel tank when various conditions exist. In one embodiment the apparatus automatically disables the magnetoelectric generator when a fuel filler cap portion of the apparatus is separated from a fuel filler flange such as when the fuel filler cap inadvertently disconnects from the fuel tank or is removed for filling the fuel tank. In another embodiment, the safety fuel tank and filler cap apparatus disallows removal of the fuel filler cap portion of the apparatus from the fuel tank when the engine is too hot, such as above a selected safe threshold temperature value.
2. General Background
The flash point of a liquid such as gasoline should not be confused with the temperature necessary to ignite the vapors, for unless a source of heat considerably hotter than the flash point of the fuel comes into direct contact with the vapors, the fuel will merely give off vapors without burning. An essential factor in the process of combustion is oxygen. Without oxygen, even the most flammable vapors will not combust. Under normal conditions, a flame draws the amount of oxygen necessary to sustain combustion from the air. When the oxygen content of the air falls below about 15%, there is an immediate extinguishment of practically all flames.
There is typically a wide temperature difference between the flash point of a fuel and the ignition temperature. For example, the flash point (vapor given off) of gasoline is minus 43 degrees centigrade (minus 45.4 degrees Fahrenheit), and the ignition temperature (heat necessary to ignite the mixture) is about 257 degrees centigrade (494.6 degrees Fahrenheit). A small flame can be drawn into lube oil which is at average room temperature and it will not burn, but with the addition of burning gasoline, vapors soon rise and burn to raise the temperature of the surrounding oil to the flash point.
Every year, fires cause serious and sometimes fatal bodily injury to operators of outdoor, yard and garden, and like implements such as lawn mowers, lawn vacuums, weed trimmers, water blasters, and the like. One of the most common safety problems is associated with the attempt by individuals to add gasoline to the internal combustion engine of a lawn mower or like implement that is still running. Sometimes, an implement gradually loosens the gas filler cap because of vibration. Typically, these implements position the fuel tank and its filler neck at or near the engine block.
Fuel that spills from the fuel tank or from a supply container when filling the tank may come into contact with hot surfaces on the engine block or accessories. If the user is not paying close attention to the gas tank and its filler cap, gasoline can begin to leak when the cap is loosened. This problem is especially acute with rear drive type implements such as all terrain vehicles, go-karts, riding lawn mowers and lawn tractors wherein the gasoline tank may be behind the operator or underneath a seat or hood preventing the user from seeing it. Many tractor style riding lawn mowers have such a hidden fuel tank and filler cap.
Many of these implements are operated by adolescent children that are not warned sufficiently by their parents about the danger of filling tanks with gasoline when the implement or vehicle is hot from operation.
Many manufacturers use decal warning stickers and user""s manual warnings to warn a user to not remove the fuel filler cap until the engine cools for at least a couple of minutes.
Generators are often filled with gasoline by a user when still running because the user does not want to interrupt the flow of electricity.
All of the above situations are hazardous if the engine continues to run when the filler cap is removed or becomes removed, or if a user attempts to fill the fuel tank when the engine is very hot.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention.
No feature of the invention is critical or essential unless it is expressly stated as being xe2x80x9ccriticalxe2x80x9d or xe2x80x9cessential.xe2x80x9d
The present invention provides an improved safety fuel tank and filler cap apparatus for supplying fuel to an implement powered by an internal combustion engine that can be started with a magnetoelectric generator. The implement can be, for example, a lawn mower, go-kart, garden tractor, lawn vacuum, snow blower, tiller, chain saw, weed trimmer, hedge clipper, or log splitter.
The apparatus includes an exposed fuel tank having a fill opening, a fuel filler flange surrounded by an adjoining fuel tank outer surface, the flange extending a short distance from the filler opening in the fuel tank wall. A filler cap fits the fuel filler flange to form a closure of the tank at the fill opening, the filler tank and adjoining fuel tank outer surface being configured to enable a user to grip and turn the fuel filler cap. A switch is interfaced between the fuel tank and filler cap that disables the magnetoelectric generator when the filler cap is removed from the fuel filler tank. This construction prevents the user from filling the fuel tank with gasoline when the engine is running.
The switch can be a magnetic switch, a photoelectric switch, or a mechanical switch, for example a button switch, toggle switch, rocker switch. The mechanical switch can be a switch that moves between operating and disabled positions, the switch including a moving member that shifts positions when the fuel filler cap is separated from the fuel filler flange.
The switch can include a magnetic switch member mounted in the fuel tank and another magnetic switch member mounted on the filler cap. The switch can include a switch member mounted on the filler cap that does not interfere with the sealing of the fuel filler flange with the filler cap, being spaced from the threads or bayonet connectors that join the cap and tank.
The filler cap can have a top, an annular skirt with internal threads, and wherein the switch member is mounted on the annular skirt in between the threads and the top. Such internal threads form a threaded engaged connection with external threads on the fuel filler flange. The fuel filler cap preferably has a top, an annular skirt with a threaded portion thereon, and an unthreaded outer surface and wherein the switch member is mounted on the annular skirt. The switch member can be mounted on an unthreaded portion of the filler cap.
In another embodiment, the present invention provides an improved safety fuel tank and filler cap apparatus for supplying fuel to an internal combustion engine that includes an exposed fuel tank having a fill opening, a fuel filler flange surrounded by an adjoining fuel tank outer surface, the flange extending a short distance from the filler opening in the fuel tank wall. A filler cap fits the fuel filler flange at the fill opening, the filler tank and adjoining fuel tank outer surface being configured to enable a user to grip and turn the fuel filler cap. A locking mechanism is interfaced between the fuel tank and filler cap that disallows removal of the filler cap. This construction prevents the user from filling the fuel tank with gasoline when the engine is still running or not running but still very hot.
The present invention also teaches and provides a powered implement having a frame, an internal combustion engine mounted on the frame that includes a magnetoelectric generator for starting the engine, and including an exposed fuel tank having a fill opening, a fuel filler flange surrounded by an adjoining fuel tank outer surface, the flange extending a short distance from the filler opening in the fuel tank wall and wherein a filler cap fits the fuel filler flange to form a closure of the tank at the fuel opening.